Since the Industrial Revolution, humans have established modern society while consuming huge amounts of fossil fuel which increases a carbon dioxide concentration in the air, and the increase of the carbon dioxide concentration is further promoted by environmental destruction such as deforestation or the like. Since global warming is caused by an increase in greenhouse gases such as carbon dioxide, Freon or methane in the air, it is very important to decrease the concentration of carbon dioxide in the air which significantly contributes to the global warming, and various researches such as emission regulation or fixation of carbon dioxide have been conducted around the world.
Among them, a copolymerization reaction of carbon dioxide and epoxide found by Inoue et al. has been expected to be a reaction capable of solving the global warming problem, and the research has been actively conducted not only in views of chemical fixation of carbon dioxide but also in view of utilization of carbon dioxide as a carbon source. In particular, a polyalkylene carbonate resin formed by polymerization of carbon dioxide and epoxide has been recently spotlighted as a kind of biodegradable resin.
Various catalysts for preparing this polyalkylene carbonate resin have been studied and proposed in the past, and as a representative catalyst, a zinc dicarboxylate-based catalyst such as a zinc glutarate catalyst in which zinc and dicarboxylic acid are bonded to each other.
Such a zinc dicarboxylate-based catalyst, typically a zinc glutarate catalyst, is formed by reacting a zinc precursor and a dicarboxylic acid such as glutaric acid with each other, and has a fine crystalline particle shape. However, these zinc dicarboxylate-based catalysts have limitations in controlling or changing the stereo structures such as a particle shape and thus, it was true that they had limitations in controlling, changing or enhancing the activity as a catalyst.
Accordingly, because it is possible to more easily control the stereo structure or particle shape, or the behavior of metal ions exhibiting a catalytic activity, there is a continuing demand for a novel catalyst candidate substance capable of more easily controlling, changing or enhancing the activity as a polymerization catalyst in the preparation of the polyalkylene carbonate resin or the like.